Internal combustion engine hydraulic fuel pump
AssigneeMagneti Marelli Holding S.p.A.
InventorFranco Ciampolini
Life of this patent
Estimating the term…
Abstract
An internal combustion engine fuel pump having at least one cylinder, in which a variable-volume pump chamber is defined; a movable piston defining the bottom of the pump chamber; at least one intake valve communicating with the pump chamber; at least one delivery valve communicating with the pump chamber; and a hydraulic/pneumatic actuating device for moving the piston back and forth with respect to the cylinder to cyclically vary the volume of the pump chamber; the hydraulic/pneumatic actuating device has a first actuating chamber located beneath the pump chamber, a second actuating chamber located above the first actuating chamber, and a control member for cyclically filling the first actuating chamber with pressurized oil.
Claims12
A fuel pump (4) for an internal combustion engine, the fuel pump (4) comprising
- at least one cylinder (11);
- a variable-volume pump chamber (22) defined inside the cylinder (11);
- a piston (12) defining the bottom of the pump chamber (22) and movable with respect to the cylinder (11) in a pumping direction (35);
- at least one one-way intake valve (26) only permitting fuel flow into the pump chamber (22);
- at least one one-way delivery valve (27) only permitting fuel flow from the pump chamber (22);
- and
- an actuating device (13) for moving the piston (12) back and forth with respect to the cylinder (11) and in the pumping direction (35) to cyclically vary the volume of the pump chamber (22);
- wherein the actuating device (13) is a fluid-actuated actuating device, which uses the thrust produced by a pressurized control fluid to move the piston (12) back and forth with respect to the cylinder (11) and in the pumping direction (35), and comprises a first actuating chamber (34) located beneath the pump chamber (22) with respect to the pumping direction (35), a control member (47) for connecting the first actuating chamber (34) to a pressurized control fluid tank (45) and to a control fluid drain tank (41), and return means (37) for exerting thrust on the piston (12) in the pumping direction (35) and in the opposite direction to the thrust exerted by the pressurized control fluid in the first actuating chamber (34);
- wherein the return means (37) comprise a second actuating chamber (37) located above the first actuating chamber (34) with respect to the pumping direction (35), and which receives pressurized control fluid.
A fuel pump (4) for an internal combustion engine, the fuel pump (4) comprising
- at least one cylinder (11);
- a variable-volume pump chamber (22) defined inside the cylinder (11);
- a piston (12) defining the bottom of the pump chamber (22) and movable with respect to the cylinder (11) in a pumping direction (35);
- at least one one-way intake valve (26) only permitting fuel flow into the pump chamber (22);
- at least one one-way delivery valve (27) only permitting fuel flow from the pump chamber (22);
- and
- an actuating device (13) for moving the piston (12) back and forth with respect to the cylinder (11) and in the pumping direction (35) to cyclically vary the volume of the pump chamber (22);
- wherein the actuating device (13) is a fluid-actuated actuating device, which uses the thrust produced by a pressurized control fluid to move the piston (12) back and forth with respect to the cylinder (11) and in the pumping direction (35), and comprises a first actuating chamber (34) located beneath the pump chamber (22) with respect to the pumping direction (35), and a control member (47) for connecting the first actuating chamber (34) to a pressurized control fluid tank (45) and to a control fluid drain tank (41);
- wherein the cylinder (11) houses the piston (12), and is bounded by two, respectively top and bottom, end surfaces (14, 15) opposite and facing each other;
- the piston (12) is cylindrical, and comprises a bottom end wall (18), which defines a wall of the first actuating chamber (34), and a top end wall (17) through which is formed a central hole (20) defining the pump chamber (22);
- and a cylindrical body (21) extends from the top end wall (14) of the cylinder (11), is inserted inside the central hole (20) of the piston (12), defines a top wall of the pump chamber (22), and houses the delivery valve (27) and the intake valve (26).
Dependencies are inferred from the claim text.